diff --git a/packages/integration/src/compiler.ts b/packages/integration/src/compiler.ts
index 33a87ac8..c2137571 100644
--- a/packages/integration/src/compiler.ts
+++ b/packages/integration/src/compiler.ts
@@ -22,11 +22,11 @@ const scanModule = (entryModule: ModuleNode) => {
   const watchFiles = new Set<string>();
 
   for (const moduleNode of queue) {
-    if (!moduleNode.id || moduleNode.id.includes('@vanilla-extract/')) {
+    if (moduleNode.id?.includes('@vanilla-extract/')) {
       continue;
     }
 
-    if (cssFileFilter.test(moduleNode.id)) {
+    if (moduleNode.id && cssFileFilter.test(moduleNode.id)) {
       cssDeps.add(moduleNode.id);
     }
     if (moduleNode.file) {
diff --git a/tests/compiler/compiler.test.ts b/tests/compiler/compiler.test.ts
index dab72690..1cd70474 100644
--- a/tests/compiler/compiler.test.ts
+++ b/tests/compiler/compiler.test.ts
@@ -225,7 +225,7 @@ describe('compiler', () => {
 
   test('throws on getCssForFile when file does not exist', async () => {
     const compiler = compilers.default;
-    let error: Error | undefined;
+    let error: Error;
 
     try {
       compiler.getCssForFile('does-not-exist.css.ts');
@@ -234,8 +234,8 @@ describe('compiler', () => {
     }
 
     expect(
-      // We know `error.message` is defined, and we want make the snapshot consistent across machines
-      normalizePath(error!.message!.replace(__dirname, '{{__dirname}}')),
+      // We know `error.message` is defined here
+      normalizePath(error!.message),
     ).toMatchInlineSnapshot(
       `No CSS for file: {{__dirname}}/does-not-exist.css.ts`,
     );
diff --git a/tests/compiler/compiler.vitest.test.ts b/tests/compiler/compiler.vitest.test.ts
index 60ad4d09..a8529fdd 100644
--- a/tests/compiler/compiler.vitest.test.ts
+++ b/tests/compiler/compiler.vitest.test.ts
@@ -15,6 +15,8 @@ expect.addSnapshotSerializer({
     '"',
 });
 
+// ! These tests are to ensure that the compiler works correctly in Vitest.
+// ! Please add tests to `compiler.test.ts` going forward.
 describe('compiler running in Vitest', () => {
   let compilers: Record<
     'default' | 'vitePlugins' | 'viteResolve',
diff --git a/tests/compiler/fixtures/tsconfig-paths/src/main.tsx b/tests/compiler/fixtures/tsconfig-paths/src/main.tsx
index d37e3782..3f304bd1 100644
--- a/tests/compiler/fixtures/tsconfig-paths/src/main.tsx
+++ b/tests/compiler/fixtures/tsconfig-paths/src/main.tsx
@@ -1,5 +1,5 @@
 import { box } from 'main.css';
 
 document.getElementById('root')!.innerHTML = `
-  <div class=${box}>hello world</div>
+  <div class="${box}">hello world</div>
 `;